Feeding micronized and extruded flaxseed to dairy cows: Effects on digestion and ruminal biohydrogenation of long-chain fatty acids

Abstract

Four lactating Holstein cows fitted with ruminal and duodenal cannulae were used in a 4 × 4 Latin square study to determine the effects of feeding micronized and extruded flaxseed on ruminal biohydrogenation (BH) and digestibility of fatty acids (FA) in the gastrointestinal tract. Four diets were formulated: a control diet with no flaxseed (C); a raw flaxseed diet (RF); a micronized flaxseed diet (MF); and an extruded flaxseed diet (EF). Flaxseed diets contained 126 g kg -1 flaxseed (dry matter basis). Experimental periods (n = 4) consisted of 21 d of diet adaptation and 7 d of data collection. Flaxseed supplementation increased (P < 0.05) intake of individual long-chain FA, reduced (P < 0.05) ruminal BH of total unsaturated C 18 , and increased (P < 0.05) duodenal flow of individual long-chain FA except for C 18:2 . Feeding flaxseed increased (P < 0.05) post-ruminal digestibility of C 18:1 , C 18:2, and C 18:3 and total tract digestibility of C 16:0 , C 18:2, C 18:3 , and of total long-chain FA. Heat treatment had no effect on ruminal BH, duodenal flow and digestibility of unsaturated FA. Ruminal BH of C 18:3 was higher (P < 0.05), while the duodenal flow of C 18:3 was lower (P < 0.05) for cows fed EF than for those fed MF. Intake and duodenal flow of C 16:0 were higher (P < 0.05) for cows fed MF relative to those fed EF. It was concluded that inclusion of flaxseed in dairy cow diets increased duodenal flow of polyunsaturated FA. However, heat treatments were not effective in protecting unsaturated FA from ruminal BH. . Les rations contenaient 126 g de graines de lin par kg (poids de la matière sèche). Les expériences (n = 4) ont duré 21 jours pour l'adaptation au régime plus 7 jours pour la collecte des données. Le supplément de graines de lin augmente (P < 0,05) l'absorption des AG à chaîne longue, diminue (P < 0,05) la BH des C 18 insaturés et accroît (P < 0,05) le passage des AG à chaîne longue dans le duodénum sauf les C 18:2 . Les graines de lin augmentent (P < 0,05) la digestibilité des C 18:1 , des C 18:2 et des C 18:3 après leur passage dans le rumen et la digestibilité globale des C 16:0 , des C 18:2 , des C 18:3 ainsi que des AG totaux à chaîne longue dans l'ensemble du tractus. Le conditionnement thermique n'a aucune incidence sur la BH dans le rumen, sur le débit du duodénum ni sur la digestibilité des AG insaturés. Les vaches recevant du LE présentaient une meilleure BH des C 18:3 dans le rumen (P < 0,05), mais aussi un ralentissement du passage des C 18:3 dans le duodénum (P < 0,05) comparativement à celles nourries avec du LM. Le taux d'ingestion et le débit des C 16:0 dans le duodénum sont plus élevés (P < 0,05) chez les vaches nourries de LM que chez celles recevant du LE. On en conclut qu'inclure des graines de lin à la ration des vaches laitières accélère le passage des AG polyinsaturés dans le duodénum. Toutefois, le conditionnement thermique ne permet pas de protéger les AG insaturés de la BH dans le rumen. Mots clés:Lin, bio-hydrogénation dans le rumen, acides gras, conditionnement thermi...

Effect of Linseed Fed as Rolled Seeds, Extruded Seeds or Oil on Fatty Acid Rumen Metabolism and Intestinal Digestibility in Cows

“…In the present experiment, digestibilities of oleic, linoleic and linolenic FA were always lower for the RL diet compared to the other diets. In contrast, Gonthier et al [15] observed a lower digestibility of the control diet compared to linseed-supplemented diets, and no difference among linseed-supplemented diets. The digestibility of the control diet may differ according to the basal ration.…”

“…The most surprising result of this experiment was the numerically higher amount of linolenic acid at the duodenum with the EL diet than with the RL diet. Other data showed either a lower amount of linolenic acid with extruded linseed [15] or no variation [14]. A part of these differences among trials may be explained by differences in technological processes.…”

“…Theoretically, since the extrusion process breaks down plant cells, it is expected that cytosolic triglycerides are more accessible to rumen bacteria than when whole seed is given, meaning they are more rapidly available for lipolysis and BH. In two experiments recently carried out with extruded linseed, Akraim et al [14] did not find any effect of linseed extrusion on duodenal FA composition, whereas Gonthier et al [15] found that extrusion increased the disappearance of linolenic acid but also increased the proportion of intermediate compounds such as trans 18:1 FA in duodenal flow. These inconsistent data need to be verified, especially because Akraim et al [14] did not measure duodenal flows while Gonthier et al [15] did not determine cis and trans 18:1 composition in detail.…”

“…In two experiments recently carried out with extruded linseed, Akraim et al [14] did not find any effect of linseed extrusion on duodenal FA composition, whereas Gonthier et al [15] found that extrusion increased the disappearance of linolenic acid but also increased the proportion of intermediate compounds such as trans 18:1 FA in duodenal flow. These inconsistent data need to be verified, especially because Akraim et al [14] did not measure duodenal flows while Gonthier et al [15] did not determine cis and trans 18:1 composition in detail. Moreover, oil within the seed needs to be compared with free oil, firstly to evaluate the effects of oil accessibility according to its form of presentation, and secondly because published experiments have focused exclusively on either linseed oil or linseed but never the two in the same experiment and in the same amount.…”

Effect of extruded cotton and canola seed on unsaturated fatty acid composition in the plasma, erythrocytes and livers of lambs

“…Since the extrusion process breaks down plant cells, it can be expected that the cytosolic triglycerides would be more accessible to rumen bacteria than when whole seed is fed, because they are more readily available for lipolysis and biohydrogenation (Maddock et al, 2006). Gonthier et al (2004) found that although extrusion increased the disappearance of linolenic acid, it also increased the proportion of intermediate compounds such as trans 18:1 fatty acids in the duodenal flow. The main goal of this study was to examine the effect of increasing levels of extruded cotton seed and canola seed on oleic acid, linoleic acid and linolenic acid concentrations of the plasma, erythrocytes and livers of male Mehraban lambs.…”